Patent GB-1418381-A (GB)
Title: Method of making casting moulds
IPC: B22C9/02
Filed: 1973-05-21
Abstract: 1418381 Foundry moulds CASHEW CO Ltd 21 May 1973 [29 May 1972] 24127/73 Headings C3N and C3R A method of making a casting mould or core comprises (a) forming a mixture of mixture of moulding sand, sodium silicate and 0À3-3% based on the weight of the mixture, of a finely powdered highly polymerized material obtained by reacting a compound of the Formula (I), where R represents hydrogen, alkyl (C 1 -C 17 ), alkenyl (C 2 -C 17 ) and n is 1 or 2, or a homopolymer of a compound of Formula (I) in which R is unsaturated, or a prepolymer of a compound of Formula (I) formed by condensation with an aldehyde, with an aldehyde or a source of aldehyde, and allowing polymerization and condensation to continue until gelation occurs, (b) forming the mixture into the desired shape and (c) hardening the mixture. The compound of Formula (I) may be phenol, cresol, paratertiary butylphenol, octylphenol, nonyl phenol, urushiol, lacrol or bhilauranol. Cashew-nut shell liquid is another preferred source of such a compound. Preferred aldehydes are formaldehyde, paraformaldehyde, furfural and glyoxal whilst preferred sources of aldehyde are hexamethylenetetramine and methylol or etherified methylol derivatives of phenol, urea or melamine. At least one additional material selected from fatty oils, e.g. linseed oil, tung oil, castor oil, soya bean oil, or dehydrated castor oil; thermosetting polymers, e.g. melamine resin or urea-formaldehyde resin; thermoplastic polymers, e.g. polyethylene, polypropylene, polyvinyl alcohol, polystyrene, polyvinyl chloride or a coumarone-indene resin; carbohydrates, e.g. starch or sugar; petroleum residues, e.g. tar or pitch; natural resins, e.g. tannin, shellac, lignin or rosin; asphalt; alkaline earth metal oxides, e.g. CaO or MgO; or red iron oxide. The amount of the additional material may be 5-80% by weight of the compound of Formula (I) or the homopolymer or prepolymer thereof. The specific examples describe the preparation of moulds from sand, sodium silicate and the following further ingredients: (1) the reaction product of a novolak, formed from the reaction of formalin and phenol under acid conditions, and hexamethylenetetramine; (2) the reaction product of the novolak of (1) and methylol melamine; (3) the reaction product of the novolak of (1) and hexamethylenetetramine together with red iron oxide; (4) the product obtained by heating the resol, obtained from reacting formalin and phenol under basic conditions, under acidic conditions; (5) the final reaction product of (4) together with dicalcium silicate; (6) the product obtained by heating the reaction product of formalin, cardanol and phenol under basic conditions; (7) the resol of (4) heated under acidic conditions together with polyethylene; (8) the product obtained by heating under acidic conditions the resin, obtained from reacting formalin, phenol and urea under basic conditions; (9) the product obtained by reacting the reaction product of linseed oil modified phenol and formalin with paraformaldehyde; (10) the reaction product of the novolak, formed from reacting formalin and cresol under acidic conditions, and hexamethylenetetramine ; (11) the reaction product of the resol, formed from reacting formalin and p-t-butyl phenol under basic conditions, and hexamethylenetetramine; (12) the reaction product of the resol, formed from formalin and nonyl phenol under basic conditions, and paraformaldehyde; (13), (14) the reaction product of homopolymerized cashew nut shell liquid and hexamethylene tetramine; (15) the reaction product of linseed oil homopolymerized cashew-nut shell liquid and paraformaldehyde; (16) the reaction product of (15) together with sodium fluoride, glyoxal, surfactant and water; (17) the reaction product of nonylphenol, paraformaldehyde and cashew-nut shell liquid under alkaline conditions which is subsequently heated; (18) the reaction product of molasses, paraformaldehyde, chromic acid anhydride, diethyl sulphate, and cashew-nut shell liquid which is subsequently heated; (19) the reaction product of heating a mixture of asphalt, cashew-nut shell polymer of Example (13), and paraformaldehyde; (20) the reaction product of asphalt, the polymer of cashew-nut shell liquid as in (13), furfural and diethylsulphate which is subsequently heated; and (21) the reaction product of heating a mixture of thiolignin, the polymer of cashew-nut shell liquid as in (13) and hexamethylenetetramine.